Rocker lifts for crawler tractors



Oct. 27, 1970 GARMAN TA 3,536,297

ROCKER LIFTS FOR CRAWLER TRACTORS I Filed Dec. 19, 1967 2 Sheets-Sheet 1 INVENTORS JAMES A. GARMAN RONALD S. MORRILL BY 2 7 I a ZTTORNE S 9 J. A. GARMAN ETAL 3,536,297

ROCKER LIFTS FOR CRAWLER TRACTORS Filed Dec. 19, 1967 2 Sheets-Sheet 2 INVENTORS JAMES A. GARMAN RONALD S. MORRILL J; p ,4 3 7 I? United States Patent 0 3,536,297 ROCKER LIFTS FOR CRAWLER TRACTORS James A. Garman, Eureka, and Ronald S. Morrill, Washington, Ill., assignors to Caterpillar Tractor (30., Peoria,

111., a corporation of Illinois Filed Dec. 19, 1967, Ser. No. 691,785 Int. Cl. B66f 7/22 US. Cl. 254-94 2 Claims ABSTRACT OF THE DISCLOSURE A lift for raising a crawler tractor under its own power and having an arcuate member for engaging the ground, a support plate maintained adjacent to and below the axis of the arcuate member by interconnecting structure for engaging a grouser plate at one end of the tractor track and supporting the tractor weight upon the lift.

In providing a lift for raising track type vehicles off the ground to accomplish repairs, for example, provision must be made for the considerable weights of such vehicles. Conventional jacks which extend mechanically or hydraulically to raise such vehicles are relatively expensive and require considerable power input. Thus, it is desirable to provide a jack or lift which raises the vehicle by employing the locomotion means of the vehicle itself. It is further desirable to provide a lift which stably supports the vehicle in a raised position and tends to prevent the vehicle from riding 01f the lift in either a longitudinal or sidewise direction. Still further, when the lifts are being employed in a service shop or similar area, it is desirable to provide a lift which does not tend to damage the shop floor while raising the vehicle off the floor. A lift having these desirable characteristics may also be employed with other types of vehicles where the lifts engage the axles or other portions of the vehicles. However, the present invention is particularly contemplated for use with crawler type vehicles and the following description of the structure and operation of the present lift particularly contemplates its use with such a vehicle.

To achieve the desired characteristics noted above, the present invention provides a simple and economical lift for raising a vehicle under its own power. The lift comprises an arcuate base member and support means for engaging a portion of the vehicle, the support means being positioned adjacent the axis of the arcuate member by suitable interconnecting structure.

The advantages of such a lift are numerous. For example, the lift is simple and economical, with no moving parts, so that a vehicle may be raised under its own power with a minimum of time and effort. The curved outer surfaces of the arcuate base members minimize damage to the floor or other surface from which the vehicle is to be raised. Further, With the support means located adjacent the axis of the arcuate members, the vehicle may be maintained in a stable raised position so that it does not tend to ride off the lift.

The above advantages will be clarified and additional advantages made apparent from the following description having reference to the accompanying drawings.

In the drawings:

FIG. 1 is a side view in elevation of the present lift;

FIG. 2 is a view taken from the left side of FIG. 1; and

FIGS. 3 through 6 are illustrativeof the manner in which the present lift is to be employed for raising a crawler type tractor.

The present lift is illustrated in both FIGS. 1 and 2 and is constructed of welded steel plate throughout so that it will support the considerable weight of a crawler type tractor. The lift has a relatively broad arcuate base mem- 3,536,297 Patented Oct. 27, 1970 ber 11 with a center of radius R. Support means particularly designed to engage a grouser or similar projection of the track of a crawler tractor is provided in the form of an angled plate 12 with a generally horizontal upper surface 13. The upper surface 13 forms an apex of the lift. Three plates 14, 16 and 17 are connected between the arcuate base member 11 and the support plate 12 in spaced apart relation to provide for vertical support in the lift. The vertical plates 14, 16 and 17 are structurally secured to the plate 12 and the arcuate base member 11 and bracing webs 18 and 19 are secured to the vertical plates adjacent the arcuate member 11. The vertical plates have inwardly curved edges, as at 21, to facilitate continued engagement of the lift with the vehicle while the vehicle is being raised upon the lift.

The present lift may be employed to raise a vehicle under its own power in a manner described below with reference to FIGS. 3 through 6. A crawler type vehicle 22 has an endless track at each side thereof, one being shown at 23. The tracks have conventional grousers 24 projecting therefrom at suitable intervals. Having initial reference to FIG. 3, one of the lifts 10 is disposed at the forward end of each track 23. The apex 13 of the support plate is positioned under one of the grousers 24 for engagement therewith. The recessed surfaces 21 of the vertical plates are positioned adjacent the track so that the support plate stays in contact with the grouser. The tractor is then driven forwardly with the tracks advancing clockwise so that engagement of the grousers with the lifts raises the forward end of the tractor. Forward motion of the tractor is halted approximately when the apex 13 of the lift is directly above a forward edge 26 of the lift. Either end of the tractor may be raised by itself in this manner and a suitable stand inserted under the tractor to support it in the raised position. However, to completely raise the tractor so that both ends are off the ground, another lift 10 is then similarly disposed at the rear of each track to have its apex 13 in similar engagement with a grouser 24. The tractor is then driven in reverse with the track 23 moving counterclockwise. This motion of the tracks tends to raise the rear of the tractor upon the rearwardly disposed lifts while the forwardly disposed lifts rock backwardly and continue to support the forward end of the tractor. Rearward motion of the tractor is terminated with the tractor positioned on the lifts as shown in FIG. 4 so that the apexes 13 of all of the lifts are generally above a central portion of the arcuate base members 11. In this position, the tractor is stabilized so that it will not tend to ride off of the lifts either forwardly, rearwardly or to either side. Forward and rearward motion of the tractor is resisted since the apexes 13 of all of the lifts, being below the center of curvature of the arcuate members, are at their lowest possible levels in this position and tractor power must be applied to accomplish either forward or rearward motion. Similarly, the pyramid like interconnecting structure and the broad base of the lifts, as best seen in FIG. 2, tends to resist sidewise motion of the tractor.

If the tractor is to be maintained in a raised position over long periods of time, it is desirable to free the lifts for use with other vehicles. To do this, the tractor may be transferred from the lifts 10 to suitable stands, as indicated at 27 in FIG. 4, by again employing the locomotive power of the tractor. To accomplish this transfer, at least one stand 27 is disposed under a forward end of the tractor as illustrated in FIG. 4. The tractor is then driven in reverse so that it tends to ride off of the forward lifts and come into engagement with the stands 27 as illustrated in FIG. 5. At this point, the lifts 10 at the forward end of the tractor are removed with the forward end of the tractor supported completely upon the stand 27. To transfer the rearward end of the tractor onto a similar stand 28, the tractor is then driven forwardly with the tracks rotating in clockwise fashion so that the tractor tends to ride forwardly off of the lifts at its rearward end. Forward motion of the tractor is terminated at a position illustrated in FIG. 6 when the weight at the rearward end of the tractor is completely transferred to the stand 28. The lifts at the rear of the tractor may then be removed. To remove the tractor from the stands 27 and 28 after repairs have been completed, the above steps are repeated in reverse order so that the tractor is raised upon the lifts to permit removal of the stands and then lowered to the ground.

We claim:

1. A lift suitable for raising a vehicle off the ground under its own power, comprising support means for engaging a portion of the vehicle and an arcuate base memher having a surface of substantially constant curvature for engagement with the ground, the arcuate base member being connected to the support means by suitable structure with its ground engaging surface arranged symmetrically about the support means and the support means disposed generally adjacent an axis of curvature for the ground engaging surface of the base member, the ground engaging surface being substantially wider than the support means, the support means being disposed between the ground engaging surface and its axis of curvature to provide both lateral and longitudinal stability when 2. vehicle is supported by the lift with its support means disposed generally vertically above a central portion of the ground engaging surface.

2. The invention of claim 1 wherein the support means of the lift comprising an angled plate and the connecting structure forming a recess below the angled plate for maintaining constant engagement between 'the support means of the lift and the vehicle.

References Cited UNITED STATES PATENTS 5/1931 Angelillo 254-94 1/1933 Cortigiano 254-94 

